/**
 * ***************************************************************************** Copyright (c) 2000,
 * 2008 IBM Corporation and others. All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * <p>Contributors: IBM Corporation - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.ltk.core.refactoring;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.ltk.core.refactoring.history.IRefactoringHistoryService;

/**
 * An undo manager keeps track of performed changes. Use the method <code>addUndo</code> to add
 * change objects to the undo stack and <code>performUndo</code> and <code>
 * performRedo</code> to undo or redo changes.
 *
 * <p>This interface is not intended to be implemented by clients. Clients should use the method
 * {@link RefactoringCore#getUndoManager()} to access the refactoring undo manager.
 *
 * <p>As of 3.1 the implementation of the refactoring undo manager is based on the {@link
 * org.eclipse.core.commands.operations.IOperationHistory} provided by the <code>
 * org.eclipse.core.commands</code> plug-in.
 *
 * <p>As of 3.2 clients which need to examine refactorings which have been performed, undone or
 * redone should use {@link IRefactoringHistoryService} for enhanced functionality.
 *
 * @see org.eclipse.core.commands.operations.IOperationHistory
 * @since 3.0
 * @noimplement This interface is not intended to be implemented by clients.
 * @noextend This interface is not intended to be extended by clients.
 */
public interface IUndoManager {

  /**
   * Adds a listener to the undo manager. Does nothing if the listener is already present.
   *
   * @param listener the listener to be added to the undo manager
   */
  public void addListener(IUndoManagerListener listener);

  /**
   * Removes the given listener from this undo manager. Does nothing if the listener isn't
   * registered with this undo manager
   *
   * @param listener the listener to be removed
   */
  public void removeListener(IUndoManagerListener listener);

  /**
   * The infrastructure is going to perform the given change. If a client calls this method it must
   * make sure that the corresponding method {@link #changePerformed(Change)} is called after the
   * change got executed. A typically code snippet looks as follows:
   *
   * <pre>
   *   Change change= ...;
   *   try {
   *     undoManager.aboutToPerformChange(change);
   *     // execute change
   *   } finally {
   *     undoManager.changePerformed(change);
   *   }
   * </pre>
   *
   * @param change the change to be performed.
   */
  public void aboutToPerformChange(Change change);

  /**
   * The infrastructure has performed the given change.
   *
   * @param change the change that was performed
   * @deprecated use #changePerformed(Change, boolean) instead
   */
  public void changePerformed(Change change);

  /**
   * The infrastructure has performed the given change.
   *
   * @param change the change that was performed
   * @param successful <code>true</code> if the change got executed successful; <code>false</code>
   *     otherwise.
   * @since 3.1
   */
  public void changePerformed(Change change, boolean successful);

  /**
   * Adds a new undo change to this undo manager.
   *
   * @param name the name presented on the undo stack for the provided undo change. The name must be
   *     human readable.
   * @param change the undo change
   */
  public void addUndo(String name, Change change);

  /**
   * Returns <code>true</code> if there is anything to undo, otherwise <code>false</code>.
   *
   * @return <code>true</code> if there is anything to undo, otherwise <code>false</code>
   */
  public boolean anythingToUndo();

  /**
   * Returns the name of the top most undo.
   *
   * @return the top most undo name. Returns <code>null</code> if there aren't any changes to undo.
   */
  public String peekUndoName();

  /**
   * Undo the top most undo change.
   *
   * @param query a proceed query to decide how to proceed if the validation checking of the undo
   *     change to perform returns a non OK status and the status isn't a fatal error. If <code>null
   *     </code> is passed in the undo proceeds if the status is not a fatal error.
   * @param pm a progress monitor to report progress during performing the undo change
   * @throws CoreException if performing the undo caused an exception
   */
  public void performUndo(IValidationCheckResultQuery query, IProgressMonitor pm)
      throws CoreException;

  /**
   * Returns <code>true</code> if there is anything to redo, otherwise <code>false</code>.
   *
   * @return <code>true</code> if there is anything to redo, otherwise <code>false</code>
   */
  public boolean anythingToRedo();

  /**
   * Returns the name of the top most redo.
   *
   * @return the top most redo name. Returns <code>null</code> if there are no any changes to redo.
   */
  public String peekRedoName();

  /**
   * Redo the top most redo change.
   *
   * @param query a proceed query to decide how to proceed if the validation checking of the redo
   *     change to perform returns a non OK status. If <code>null</code> is passed in the undo
   *     proceeds if the status is not a fatal error.
   * @param pm a progress monitor to report progress during performing the redo change
   * @throws CoreException if performing the redo caused an exception
   */
  public void performRedo(IValidationCheckResultQuery query, IProgressMonitor pm)
      throws CoreException;

  /** Flushes the undo manager's undo and redo stacks. */
  public void flush();

  /** Shut down the undo manager. */
  public void shutdown();
}
